3. FMNH2 passes e-s one by one to CoQ (through series of iron-sulfur clusters)

FMNH2 has stable radical state.

4. Complex I simultaneously pumps 4 protons to intermembrane space.

1. Why aren't H+ pumped out from Complex II from FADH2?

1. B/c standard reduction potential of FADH2 is only slightly less than that of CoQ --> no H+ are pumped out.

Describe mechanism of Complex III (6)

Describe Mechanism of complex IV (8)

1. For each molecule of O reduced, how many protons are transferred from matrix to IM space for NADH? for FADH2?

2. How many matrix protons are used to build 2 waters from O?

3. How is free energy released by redox steps stored?

4. How are protons transferred back to matrix? via what mechanism? What is their role?

1. 20, 12

2. 4

3. Stored in proton gradient produced

4. all of them via ATP synthase to indirectly drive ATP synthesis by changing B-conformations in F1

1. Where is ATP synthase found?
2. What is the function of ATP synthase?
3. What drives the production of ATP?
4. What Is another word for ATP synthase?
5. What are the two distinct components of ATP synthase and where are they found?

1. Embedded in inner mitochondrial membrane

2. To catalyze formation of ATP from ADP + Pi (w help from proton-motive force)

3. Proton motive force

4. Complex V

5. F1 (peripheral membrane protein) and Fo (part of membrane)

1. What happens if you don't have F1?
2. On the enzyme surface what is the free energy change for ATP + Pi --> ATP + H2O?
3. Why does ATP synthase favor ATP production?

1. System can still catalyze e- transfer from NADH to O2, but can't produce proton gradient --> can't make ATP.